In addressing the issue of declining sales for a retail company, four distinct approaches can be applied to thoroughly understand and resolve the problem. The issue-driven approach focuses on dissecting the problem to understand its essence, such as identifying whether the decline is due to specific product categories, customer segments, or regions, and comparing performance with competitors. The hypothesis-driven approach involves formulating potential causes, such as new competitors, misaligned product offerings, ineffective marketing strategies, or economic changes, and then planning data collection and analysis to verify these hypotheses. The output-driven approach emphasizes envisioning the desired outcomes, like sales trend graphs by product category, purchasing behavior analysis by customer segment, market share comparisons, and summary reports of hypothesis verification, to guide efficient data analysis. Finally, the message-driven approach simplifies complex analysis into core messages for stakeholders, such as highlighting that the sales decline is primarily due to the loss of young customers aged 18-25, driven by competitors' effective online marketing strategies, and recommending enhancing the company's digital presence. Combining these approaches allows for a comprehensive understanding of the problem, the development of effective solutions, and clear communication of actionable insights.